There are many serious environmental concerns regarding internal combustion engines employed in motor vehicles. Such engines cause irreversible pollution, operate at low efficiencies, and require the combustion of non-renewable fossil fuels. In response to this pollution crisis, car manufacturers are working diligently at developing alternative energy systems, which do not require combustion reactions.
Alternatives to internal combustion engine powered motor vehicles have included various types of electric vehicles. Typical electrical vehicles are powered by nickel cadmium batteries which are rechargeable by stationary direct current power supplies. These systems suffer from many disadvantages. Since the batteries require constant recharging, these cars are not well suited for driving long distances. Additionally, these types of cars generally are not adapted for highway driving, as they are considered to be underpowered. Moreover, due to the weight of the batteries, these types of cars tend to be heavy, which in turn impairs their performance. With current technology, such electronically powered cars are prohibitively expensive.
Various hybrid vehicles have been proposed. Typically, hybrid vehicles have two power sources and are intended to improve overall fuel efficiency. A basic design principle for many hybrid vehicles is based on the concept that power demands for a car or another vehicle fluctuate over a wide range; thus, the intention is to provide one, efficient power source that provides a certain base power requirement and another power source that provides the additional power required to meet peak power requirements.
One type of hybrid vehicle utilizes a combination of a fuel cell and an internal combustion engine to provide sufficient power to propel the vehicle. However, using current technology, such vehicles are expensive to manufacture and operate. Furthermore, since a typical vehicle is only used for a small fraction of the time, the fuel cell is underutilized. Accordingly, without a secondary use for the fuel cell, the high capital cost of the fuel cell is not justified.
Different types of fuel cells including proton exchange membranes, solid oxides, high temperature fuel cells, and regenerative fuel cells have been explored for use in motor vehicles. Currently, most of the research is directed towards a proton exchange membrane fuel cell comprising an anode, a cathode, and a selective electrolytic membrane disposed between the two electrodes. In a catalyzed reaction, a fuel such as hydrogen is oxidized at the anode to form cations (protons) and electrons. The ion exchange membrane facilitates the migration of protons from the anode to the cathode. The electrons cannot pass through the membrane and are forced to flow through an external circuit thus providing an electrical current. At the cathode, oxygen reacts at the catalyst layer, with electrons returned from the electrical circuit, to form anions. The anions formed at the cathode react with the protons that have crossed the membrane to form liquid water as the reaction product. Typically, a combustion reaction is not involved. Accordingly, fuel cells are clean and efficient.
One drawback associated with the known prior art fuel cell systems, however, is that they are not economically viable for use in a vehicle. Typically a vehicle requires a fuel cell with a power rating of at least 20 kW to be able to meet propulsion demands. Given the current production costs for fuel cells, a fuel cell power unit of sufficient size for a car represents a significant investment and in effect, greatly increases the initial cost of the car. Even though there are significant fuel cost savings with a fuel cell power unit, the ongoing savings throughout the lifetime of the car do not justify the higher initial capital costs of current fuel cell technology.
Several proposals for addressing this problem can be found in issued patents. U.S. Pat. No. 5,858,568 provides for off-board use of the electricity generated from at least one stationary fuel cell powered vehicle. U.S. Pat. No. 5,767,584 and U.S. Pat. No. 6,107,691 both disclose inventions for generating electrical power from multiple stationary fuel cell powered vehicles parked in a parking lot. All of these inventions are based on the realization that a fuel cell power unit of a car represents a significant power source, and unlike a conventional combustion engine, can efficiently generate electrical power that can be readily taken off the vehicle for use elsewhere. Furthermore, a fuel cell can generate electricity virtually free of pollution, whereas an internal combustion engines, produces greenhouse gases which contributes to acid rain. Moreover, unlike conventional gas engines, the wear and tear from additional use of a fuel cell is quite small. Thus with suitable financial incentives, it is believed that vehicle owners would effectively be prepared to rent out the power unit of a vehicle simply as an electrical generator, when the vehicle is not in use. Payments made for use of a vehicle's fuel cell power unit effectively provides the subsidies necessary to justify the higher initial capital costs of the fuel cell powered vehicle. A further consideration is that fuel cell engines are powerful, typically in the range of 20 kw to 40 kw, so that the power of the order of Megawatts would be generated from a small number of vehicles. To enable power to be recovered from a large number of vehicles, the intention is to provide a suitable facility at a parking lot or the like.
According to U.S. Pat. No. 6,107,691, a parking lot is equipped with individual docking stations, each providing a fuel line, and an electrical receptacle for connection to an electric cable. An electric power grid is electrically connected to the electrical receptacles in the parking lot for transferring direct current (DC) electrical power from the fuel cells in the parked vehicles to an electric power collection station. The electric power collection station is then electrically connected to the electrical power grid for transfer of electric power after conversion to alternating current (AC) to the end user. At least one inverter is provided in the electric power collection station for converting the DC electric power to AC electric power. In this distributed energy system, parked vehicles can be operated and the resulting energy harnessed and distributed through an electric power grid to provide electrical power for local or distant use.
Although the known prior art systems describe some of the technical aspects of the distributed energy system, these known proposals do not specifically address the overall communication system and method required for this system to work properly and efficiently; in particular, they fail to provide systems and methods for accounting for fuel used and electricity generated. Clearly, as compared with any fixed generating plant, a vehicle-borne fuel cell unit is mobile, and this presents unique requirements such as identifying the vehicle, and providing metering and billing for fuel consumed and electricity generated by the vehicle. Without an overall communication network, it is conceivable that the participants in such a scheme would have to separately negotiate contracts before receiving all of the relevant information. For example, an owner of a fuel cell powered vehicle may have to set or agree to an electricity supply price, or vice versa a fuel price. In this scenario, the fuel cell powered vehicle faces a disadvantage of having to negotiate a contract without all of the relevant information required for economic power generation. This type of uncertainty leads to an inefficient energy market. Additionally, there would be substantial accounting and record keeping complexities.
Conventionally many utilities, such as electricity, gas and the like have been distributed by large companies, which often have a monopoly for distribution in a particular area. Additionally, pricing for energy supplies such as electricity has been inflexible and based on long term contracts. For example, the price of electricity is set, and in many jurisdictions, is subject to government regulation, for time periods of the order of months or years.
More recently, the concept of ‘distributed generation’ is becoming recognized. Generally, ‘distributed generation’ is seen as the supply of electricity at a point closer to the consumer than traditional power plants thus reducing the requirements for electricity transmission and optimizing power plant system efficiencies. Distributed power plants could provide power to a single user or to an entire grid, but in either case are typically expected to be a few orders of magnitude smaller in power output than centralized power plants.
Many people believe that distributed generation will change the format of the electricity grid in the 21st century, as the consumer gains more control over their electricity choices in source(s), distribution and transmission. The technology used for distributed generation, coupled with the Internet, provides a unique opportunity to enhance the efficiency of the electrical power industry.
A distributed power plant system that is optimized using currently available technologies could be described in numerous ways. For example, a high efficiency, low emission vehicle-borne fuel cell can provide the basic power source for a vehicle; additionally, it could be used to provide power to the grid during non-driving periods. Such a concept would enable more efficient use of existing technologies and vehicles. These fuel cell-powered vehicles would require a fuel to operate (hydrogen in its simplest form) and could utilize any fossil fuels containing hydrogen (e.g. natural gas or methanol) either on board or from a central generating station for this purpose. With a suitable interconnection device, these cars can be plugged in wherever they are parked, for example at the owners place of employment, and could be refueled and provide power at the same time to the main grid (for centralized distribution) and for their specific location (distributed generation, UPS and high reliability in the order of 99.9999% of power generation).
Other technologies for distributed generation could include diesel generators, micro-turbines, wind, solar and hybrid combinations of these generators. However, the main interest of the present invention pertains to vehicular fuel cells. Nonetheless, it should be recognized that, in any distributed generation scheme, fuel cells are unlikely to be the sole source of distributed generation power.
In practice, fuel cells are not operated as single units. Rather, fuel cells are connected in series, stacked one on top of the other, or placed side by side. A series of fuel cells, referred to as fuel cell stack, is normally enclosed in a housing. The fuel and oxidant are directed through manifolds to the electrodes, while cooling is provided either by the reactants or by a cooling medium. Also within the stack are current collectors, cell-to-cell seals and insulation, with required piping and instrumentation provided externally of the fuel cell stack. The stack, housing, and associated hardware make up the fuel cell module.
However, the present invention provides for an extension of the typical fuel cell stack whereby, in addition to connecting the fuel cells in series, stacked one on top of the other or placed side by side, the fuel cells become connected through the grid and the Internet, forming a meta-network of energy generation.
Fuel cells may be classified by the type of electrolyte, either liquid or solid. The present invention can apply to any type of fuel cell.
The fuel commonly used for such fuel cells is hydrogen, or hydrogen rich reformate from other fuels (“reformate” refers to a fuel derived by reforming a hydrocarbon fuel into a gaseous fuel comprising hydrogen and other gases). Alternatively, the hydrogen may be generated by one or a combination of the sources, including, but not limited to, wind, solar, bacteria, nuclear, hydroelectric, cold fusion, methane derived from coal beds, or methane hydrate from the ocean floor. Hydrogen could also be generated by electrolysis, but clearly as the present invention essentially proposes consuming hydrogen to generate electricity, this will likely only be commercially feasible where hydrogen can be generated economically using cheap, off-peak electricity, stored, and then used to generate electricity during a peak rate period. The oxidant on the cathode side can be provided from a variety of sources. For some applications, it is desirable to provide pure oxygen, in order to make a more compact fuel cell, reduce the size of flow passages, etc. However, it is common to provide air as the oxidant, as this is readily available and does not require any separate or bottled gas supply. Moreover, where space limitations are not an issue, e.g. stationary applications and the like, it is convenient to provide air at atmospheric pressure. In such cases, it is common to simply provide channels through the stack of fuel cells for flow of air as the oxidant, thereby greatly simplifying the overall structure of the fuel cell assembly. Rather than having to provide a separate circuit for oxidant, the fuel cell stack can be arranged simply to provide a vent, and possibly, some fan or the like, to enhance air flow.
The fuel can be supplied from fossil fuels but needs to be converted to hydrogen before use in the fuel cell. This conversion is typically performed with some sort of reformer. Presently, there are three general types of reformers: partial oxidation, auto thermal and steam. These reformers vary greatly with respect to operating conditions, size, efficiency, etc. However, a reformer is required with any fuel cell system when hydrocarbon fuel is used.
A fuel cell operates at its highest efficiency while idling or supplying minimal power, in contrast to internal combustion engines, which operate at their lowest efficiency while idling or supplying minimal power. In a fuel cell, as the power output increases to the peak output power, the efficiency correspondingly decreases. Fuel cells operating at low utilization offer advantages over traditional power plants because they will generate power at potentially higher efficiencies than these power plants. Using the United States as an example, the total amount of electrical power required for industrial and residential use is provided repeatedly by new car production every year. Consequently, the concept of underutilized, high efficiency fuel cells becomes attractive for distributed generation. In fact, a grid supported primarily by many parked vehicular distributed generation plants may be the future of the energy industry, and may replace most if not all of central generation. Even a relatively small number of vehicles could provide the equivalent of 1 MW of power, over a large number of locations.
Accordingly, there exists a need for a network communication system and method for enabling the real time buying and selling of electricity generated by fuel cell powered vehicles parked in a parking lot or the like. Specifically, there is a need for a system and method for energy trading that provides for: proper metering and billing for fuel used and energy generated; timely and accurate communication between all of the participants; and, availability of unbiased information to all of the participants.